Heat exchanger



May 16, 1944. s. .1. CHUTE Erm.

HEAT VEXCHANGER Filed July' 17 2 sheets-Sheet 1 i g a s s a :s

' (((CKKCC INVENTOR STANLEY J. CHUTEI BY HERMAN F. BuscHow 4. Aang@ A ORNEY ay 16, E944. J. CHUTE Erm.

HEAT EXGHANGMER Filed July 17 1940 2 v IEW m' "v nu s 2 Sheets-Sheet 2 INVENTOR STANLEY J. CH BY HERMAN F. BUSC W LA un df. am@ `rToRNEY FIG. .3

Patented May 16, 1944 UNITED STATES PATENT fol-FICE F. Buschow, Flushing, N. Y., assignors to The M. W. Kellogg Co., New York,'N. Y., a corporavtion of Delaware Application July 17, 1940, Serial No. 345,888 3 Claims. (Cl. 257-234) This .invention relates toheat exchangers, and

particularly to that type of lheat exchanger in which one fluid heat-exchange medium is passed through a tube, or a series of tubes, in which a nest, or nests, of smaller tubes is disposed to provide passage for another fluid heat-exchange-medium.

The United States patent to Wilson et al, No. 2,125,972, issued August 9, 1938, discloses a heat exchanger oi the type contemplated by this invention. Heat exchangers of this. type, because of their rugged and simple construction, their high thermal emciency, and their high heattransfer capacity per unit of Weight, have gone into successful commercial use in installations where operating conditions are particularly severe or extreme. These heat exchangers have been successfully used as transfer-line heat err- Fig. 3 is a section view of the tube nest .taken along line 3 3 of Fig. 24.

Heat exchanger unit il comprises aepair of comparatively large tubes or shells l2 for conducting one heat-exchange medium; anest of smaller tubes l 3 encased within each of the shells to form a fluid passage therethrough for aA second heat-exchange medium; a return-bend, .generally4 indicated'at'lt, including means for connecting adjacent shell ends and adjacent tube nest ends; and a connecter i5 on the free end of each shell i2?, the connecters i5 and portions of the shells adjacent the connectors being adapted to provide an ingress and an egress for the fluid changers'n the petroleum refining art and, in

such use, have handled fluid media at pressures n above 2000 lbs. per square inch and at temperatures higher than 1000 ii.

The ,heat exchanger of the present. invention is in the nature ci an improvement of the heat exchangerfdisclosed in the Wilson et al patent above-identified.

it is a principal object oi this invention to proride a heat exchanger of the type mentioned, of

simple, lightweight, and sturdy construction,

havingan improved arrangement of units Whereby the heat exchanger may readily be disassembled for purposes or cleaning, repairing, or inspection.

A further object of this invention is to provide a heat exchanger of the type mentioned in which the shell system and tube nest system are readily separable.

.il still further object is to provide a heat exchanger of the type mentioned, particularly suited for high pressure service, in which each tube nest has novel end arrangements forming therewith a unit removable, as such, from the tubular shell with a minimum of dismantling of the surrounding parts.

Further objects and advantages of this invention will be apparent from the following description and claims taken in connection with the accompanying drawings, in which: Y

` Fig. 1 is a side view, in half-section, of one of a plurality of heat exchanger units arranged in a bank.

Fig. 2 is an enlarged section view of one of the l tube nests showing the stationary and the oating end construction; and

tion, to

passages formed by the connected shells and the connected nests of tubes.

In a typical heat exchanger installation, a se#- ries of such units ii may be joined together and supported on a framework-in a manner similar to that shown and described in the aforementioned patent to Wilson et al. Since the present invention is directed to improvements 'and modications in the unit described therein, it is unnecessary, or a'complete understanding of this invendo more than illustrate and describe a single unit, attention being speciiically drawn to the novel departures in design and construction constituting the improvements.l

The shells i2, which ordinarily conduct the low pressure medium, are'adjacent and parallel.

at each end with the adjacent sWaged-out sections it to form a fluid cross-over between the shells i2. The ends of pipe I8 extend through f openings formed in the walls of sections I6, and

are joined thereto by welds I9.

A flange plate 2l, having two openings 22 spaced center-to-center a vdistance equal to that between the shells i2, is attached to those ends oi shells i2 which are adjacent crossover pipe i8. Each opening 22 aligns with one of the shell passages. The'end of each shell is joined, as by weld 2t, to a short annular neck 23 formed around each opening 22 of the ange plate 2 i. The face of flange plate 2l is dishedout around each opening 22 to form rabbeted portions 25. A removable bonnet 26 is secured to flange plate 2 I. Studs '21, set in the bonnet, extend through holes 28 in shell.

the flange plate and have nuts 23 thereon which hold the bonnet to the flange plate in fluid-tight engagement. Bonnet 28 also forms a fluid crossover for the shell passageways. Pipe I8, however, forms the main cross-over for the fluid medium in the shell; and bonnet 28 serves to carry over only the fluid seeping past the floating tube sheets, as will be more fully explained hereinafter.'

Individual, outwardlyl flaring flanges 3| are attached, as by welds 32, to the opposite ends of shells I2. Connector I5 is attached in fluidtight engagement to shell ilange 3| by circumferential row of studs 33 and nuts distributed around the flange. Studs 33 are set in the face of lange 3| with their projecting-ends extending through holes in the connector I5. A

t corresponding to, and in alignment with, the

threads to bite into the surface of the tube. The

the area between the end of the inserted tube and the outer face of the tube sheet, provides a small ledge or recess around which an annulus of weld metal 48 is deposited to rigidly secure the tube to the tube sheet.

Connecter'15 has a plurality of openings 5I holes in the tubel sheet 48. The openings 5| are in a diaphragm 52 formed across the mouth of the connecter passageway 53. A frusto-conical portion 54 is formed within the connecter pasprojecting pin 35, set in the face of flange 3|,

and a recess 38 formed in the connector cooper ate as a guide means to maintain a proper relative position vbetween the connector and the Connector I5 includes tion 31 which forms a 90 elbow on the end of the shell. The tube nest I3 isso arranged withva `curved tubular por-- in the shell that its tubes connect with the the 'interior of the shell I2 through the flaring side of flange 3|. Connector 38 comprises a flange 39 joined to the end of a. curved pipe 4| by weld 42. The other 'end of pipe 4| extends through an opening in the-side of flange 3| and` is secured to the latter by weld 43.

Asshown, the shell system of the heat exlchanger unit is substantially U-shaped, each -shell I2 forming one branch of the U. The connecters I5 and 38, associated with each brancl'l of the U, curve outwardly from the end of the unit with their fluid passageways discharging in the same direction, that is, normal to the longitudinal axis of the shell. AThe flange faces of the connectors. I5 and 38 are in a common plane parallel to the shells I2, so that a series of units II may readily be connected together in a bank, with all of the shells arranged in parallel fashion. Sealing-ring grooves 44 are provided in the face of each connecter flange, so that, with the use of a sealing ring, a fluid-tight connection may be obtained between the adjacent heat exchanger units. Flange bolts 45, distributed about the flanges, provide a rigid coupling for the units,

' and enable them to be easily assembled or dis` assembled.

sageway adjacent and behind the diaphragm 52.

'The portion 54 ofthe connecter passageway taf,v`

pers from a cross-sectional area at one end large enoughto include the openings for the nest of tubes .to a cross-section area at the other end approximately equal to the sum of the flow areas of all the' tubes in the nest. `The openings 5I inthe connecter diaphragm 52 are fitted with removable bushings 55 which may be replaced periodically as they become corroded by the flow l A gasket 58 is positioned between tube sheet I 48 and the face of connecter I5 to prevent fluid y leakage between the shell and the nest of tubes.

Gasket 58 covers diaphragm 52, and has cut-out portions aligning with openings 5| and hole 51.

As illustrated in Fig. l, the inlet for the medium conducted by the tube shell and the outlet for the medium conducted by the nest of'tubes are shown in section. An impingement baille The tube nest .I3 ofeach shell includes a stationary and a floating tube sheet into which the ends of the tubes' are set. The stationary end of the nest is rigidly secured to connectorl I5, and the floating endthereof extends through Bange plate 2| into thc bonnet 28.. In the particular embodiment illustrated, the tube nest comprises three tubes equi-spaced from each other and from the shell I2, as clearly shown in Fig. 3. The stationery tube sheet 48 is secured to connecter I5 byvstuds 41 set in the face of the connecter ange.

` Stationery tube, sheet 48, shown enlarged' in Fig. 2, has a plurality of holes, corresponding to the number of tubes in the tube nest, adapted to receive and hold the ends of the tubes.A Each portion of its depth, as at 48. Each tube end is inserted into the threaded portion of the hole,

vhole in the tube sheet is threaded lightly for a and is rolled outwardly therein to cause the 15 deformed and interlocked'with the 5| is placed within the flange member 3| in a position to shield the tubes I3, so that they will not receive the full force of the fluid admitted through connector 38. Batlle 8| comprises' a curved shield 82, adjacent and partially surrounding the end of the tube nest, and -a lateral brace 83 mounted on the free end of stud 41 and held firmly in position by nut 84,

I'he opposite end of tube nest I3 is designed to i'ioat within the shell, so that the tubes may freely expand and contract longitudinally therein with changing temperatures. 'l'he floatingdiameter equal to the bore of tubes I3. and,a y longer zone-88 into which tubes I3 maybe inserted. The tube receiving zone 88 is treated to provide a surface of sharp irregularities, as by cutting a screw thread therealong, so that the tube ends, when inserted and rolled outwardly therein, will have their outer surfaces surfaces of the tube sheet holes. 1

-Zone 88 is only partially occupied by tube I3. sumcient space being left between the end therer y 2,s4o,14's 'of and zone sa to provide a channel ihm which weld metal 1I may be deposited to rigidly secure the tubes to the tube sheet.

Tubes I3 are arranged on the shortest centerto-center distances possible with the type of tube4 sheetl construction shown;l so that a one-to-one ratio may be'closely approximated between the flowv area of the shell I2 and the combinedcrosssection ilow areas ofthe tubes I3, as will be apparent from a consideration of Fig. 3. To compensate for this, ller rods 12 are placed in the tube nest to decrease the ilow area oi' shell I2, so that it closely approximates the flow area of the tube nest.

The rods 12 are shorter than the distance between the tube sheets. and are supported at their ends -by dowels 13 firmly set in the tube sheets. The projecting ends of dowels 13 are received in holes 14 drilled longitudinally in the ends of the rods. The dowel length and the depth of holes 14 are such that the rods may easily be inserted and 'removed independently of the tubes. In assembling the tube nest, the rods are slipped onto the dowels and then centered between the tube sheets. In this position, the rods are rigidly secured at one end to the dowels, as by a small deposit of weld metal; the other end is left unconnected to allow free longitudinal expansion of the rods.

A reducing nipple 15, having an outside diameter equal to that of the tube sheet 85, is joined to the latter by weld 18.- The bore of nipple 15 tapers from a diameter, adjacent the tube sheet. equal to the bore of recess 31 to a diameter, at its outer end, sumcient to provide-a now area substantially equal to the` total flow area of the nest of tubes. p

A return bend 11 within the bonnet 28 connects the ends of the tube nests In the adjacent shells I2. The ends of the return bend 11 and the outer ends of the reducing nipples 15 are suitably grooved to receive a sealing ring 1l.

A yoke 19 is provided at each end of return bend 'llll to hold the latter in fluid-tight engage-- ment with the floatingl end o! the tube nest. One end of yoke 19 is formed into a ring 80 adapted to encircle the reducing nipple 15. Ring a has an annular shoulder BI extending inwardly which engages the projecting edge of a split-ring 02. Split-ring `32 has a shoulder extending inwardly which fits intoa circumferential groove on the surface ofthe nipple 13.

The remaining portion of yoke partially encases the end of the return bend 11. A crossmember 8a at the open] end of the yoke is drilled and tapped to receive a screw 34 which may be made to press against the end 0f the return bend 11 to maintain a duid-tight connection between I the latter and the tube nest. The entire floating end oi the tube nest, including the tube sheet til, nipple 15, return bend 11, and yoke 19, may thus move longitudinally with changing temperatures within the shell and the bonnet. The'iilow path thus formed by the nests civ tubes and the return bend -is completely sealed since the escaped fluid may cross over .through the bonnet and pass into the shell on the opposite side. Drain plugs 35 are provided in the bonnet 2B for the evacuation of the accumulated iluid therein when the bonnet is to be removed from the flange plate 2I.

The heat exchanger unit I`I is assembled in the following manner: The tubes I3 are Vset in the tube-sheets 43 and 55. and the tube ends then are rolled outwardly. Welds 49 and 1I are then made to join the ends of the tubes to the tube sheets. The filler rods are inserted and tack-welded, or otherwise secured, at one end to the dowels projecting from the tube sheets. The reducing nipple 15 is welded to tube sheet 65. Stationary tube sheet 46is joined to connecter I5 by studs 41, gasket 58 being'placed therebetween to .provide a fluid-tight joint. Batlle 6I is mounted on the projecting end of stud 41. The assembled tube nest is then pushed through the shell until the flanged connecter I5 engages ange 3I. Nuts 34, on the ends of the studs 33 which project through the connecter. are used to hold the shell and the connecter -tightly together. tionary end of the heat exchanger unit is complete, and the reducing nipple 15 and part of the tube sheet 65v extend through opening 22 in the ilange 2|. `Yoke 19 is slipped over` the end of nipple 15 and slid inwardly into the rabbeted portion 25 of the flange 2| until the tube-sheet encircling ring 80 of the yoke 19 clears the groove which accommodates the split-ring. The split-ring B2, which is in three parts, is then 1nserted piece-by-piece into the groove at the most accessible pointl each piece being slide around I tion, the return bend 11 is slipped .in place.

Sealing rings 18 are placed between the return bend and the reducing nipples 15, and screws 54 are advanced until sufilcient pressure is exerted against the return-bend 11 to provide a fluidtight connection between the latter and the tube nest. Bonnet 26 is then secured to the flange 2I.

The construction of unit II is such that it has the advantage of being easily and quickly disassembled for the purpose of cleaning or repairing. To disassemble the unit, bonnet 23 is removed and screws 84 are backed upto release return-bendv 11, which is also removed. Yokes j 19 are-slid forward on the tube sheet 65, permitting the split-rings 82 to be removed. The yokes 19 are then removed from the end of the tube nest. At the stationary end of the unit, nuts 34 fromthe shell. and the bonnet. yAlthough some of the fluid in the shell, instead idf passing through the cross-over pipe I3 may leak between arey removed from their studs 33 to'release connecter I5 from flange 3|. The entire tube nest, being attached to connecter I5 by the studs 41, is then removed as a unit with the connecter.

The parts of the apparatus most easily af- '.i'ected by the corrosive action of the fluids are ,thus made easily accessible for the purpose of replacement or repair. Although bushings B5 arev fitted into the openings 5I oldiaphragm 32 -to decrease corrosion therein, periodic replacement may be necessary. While the tube nest is re- -moved from the shell I2, the connecter I5 may be separated from the tube sheet 4E by removing the nuts from studs 41. New bushings may then beplaced, if required, in the diaphragmnf connecter I5. A particular advantage of the novel arrangement shown and described is that the various As thus assembled. the stanozzlesfilanges, tube sheets, etc. may be of lighter construction than has heretofore been possible. A considerable saving in weight isA thus effected, which applies not only to the various parts of the heat exchanger. unit, but also to its supporting structure. construction of the unit permits the use of shorter and lighter bolts for connecting the various parts. These weight-saving features of the unit appreciably affect the cost of construction, and serve to maintain it at a minimum. A fur- 1 ther advantage to be gained by the use of lighter and smaller parts is that the heat exchanger as a whole is given greater ilexibility.

We claim:

1. In a heat exchanger, a nest of tubes; a shell encasing said nest of tubes; a connecter attached to the end of said shell, said connecter having a diaphragm integral therewith extending across the end adjacent said shell provided with a plu- 2. In a heat exchanger of the character described, nest of tubes; a, shell encasing said The compact and sturdy rality of passages corresponding to -said tubes and replaceable linings within said plurality of passages; a tube-sheet having partly threaded tube holes, the'ends of said tubes being expanded within the threaded portionsthereof; and annuli of deposited weld metal uniting the ends of said tubes to said tube-sheet and lining the remaining portions of said tube holes; said tube-sheet being secured within said shell to said connecter with said tube-nest passages and said diaphragm passages joined in duid-tight connection. v

nest of tubes; a ilanged connecter attached to the end of said shell, said connecter having a central passage closed at the end adjacent said shell by a substantially thick, perIor'ate diaphragm integral with the body of the connecter, the flange face and diaphragm closing the end of said shell; a tube-sheet for said tubes having openings corresponding to and aligning with the perforations Aof said diaphragm, said tube-sheet being removably attached in fluid-tight relation placeable linings therein; and a tube-sheet for.

said tube nest secured within said shell to said connecter, said tubes and said lined passages having substantially equal flow areas and being connected in fluid-tight relation.

STANLEY J. CHUTE. HERMAN F. BUSCHOW. 

